test/uninit.cc

   1 /**
   2  * @file uninit.cc
   3  * @brief Uninitialized loads test
   4  *
   5  * This is a test of the "uninitialized loads" code. While we don't explicitly
   6  * initialize y, this example's synchronization pattern should guarantee we
   7  * never see it uninitialized.
   8  */
   9 #include <stdio.h>
  10 #include <threads.h>
  11 #include <atomic>
  12
  13 #include "librace.h"
  14
  15 std::atomic_int x;
  16 std::atomic_int y;
  17
  18 static void a(void *obj)
  19 {
  20         int flag = x.load(std::memory_order_acquire);
  21         printf("flag: %d\n", flag);
  22         if (flag == 2)
  23                 printf("Load: %d\n", y.load(std::memory_order_relaxed));
  24 }
  25
  26 static void b(void *obj)
  27 {
  28         printf("fetch_add: %d\n", x.fetch_add(1, std::memory_order_relaxed));
  29 }
  30
  31 static void c(void *obj)
  32 {
  33         y.store(3, std::memory_order_relaxed);
  34         x.store(1, std::memory_order_release);
  35 }
  36
  37 int user_main(int argc, char **argv)
  38 {
  39         thrd_t t1, t2, t3;
  40
  41         std::atomic_init(&x, 0);
  42
  43         printf("Main thread: creating 2 threads\n");
  44         thrd_create(&t1, (thrd_start_t)&a, NULL);
  45         thrd_create(&t2, (thrd_start_t)&b, NULL);
  46         thrd_create(&t3, (thrd_start_t)&c, NULL);
  47
  48         thrd_join(t1);
  49         thrd_join(t2);
  50         thrd_join(t3);
  51         printf("Main thread is finished\n");
  52
  53         return 0;
  54 }